The invention relates to a removing apparatus for removing defective rod-like articles from a transport path while rod-like articles are being transported along the transport path, particularly to a removing apparatus suited for a filter cigarette manufacturing machine.
A filter cigarette manufacturing machine has a transport drum train comprising rotatable transport drums. The transport drums are adjacent to each other and form a transport path for rod-like articles such as cigarette rods and filter plugs which are used in manufacturing filter cigarettes. While cigarette rods and filter plugs are transported along the transport path, various steps for forming filter cigarettes from the cigarette rods and filter plugs are carried out sequentially.
Specifically, while the cigarette rods are transported, each cigarette rod is cut into two equal cigarettes, and then a filter plug is supplied to between those two cigarettes. The cigarettes and filter plug are connected by a tip-paper piece to form a double filter cigarette, and then the double filter cigarette is cut into two equal filter cigarettes.
Among the transport drums in the transport drum train, at least one transport drum functions as a removing drum. When rod-like articles, namely, cigarettes, double filter cigarettes or filter cigarettes pass across the removing drum, the removing drum removes them from the transport path. This is performed in order to sample rod-like articles or prevent defective rod-like articles from being transported in the downstream side of the removing drum.
Like the other transport drums in the transport drum train, the removing drum has many transport grooves on its outer circumferential face. As the removing drum rotates, rod-shaped articles are transported, being held in the transport grooves by suction pressure. More specifically, the removing drum has a suction supply region which extends in the circumferential direction thereof, and each transport groove has a plurality of suction holes for receiving suction pressure from the suction supply region. Hence, each transport groove can receive suction pressure through its suction holes while the transport groove is passing through the suction supply region extending in the circumferential direction of the removing drum.
In the suction supply region, a suction holding region is so arranged that the suction holding region severs the suction supply region. While the suction holding region can normally supply the transport grooves with suction pressure enough to suck and thereby hold rod-like articles in the transport grooves, it can selectively receive compressed air from a compressed air ejecting means.
Specifically, when a rod-like article which should be sampled or removed passes through the suction holding region, being held in a transport groove, compressed air is supplied to the suction holding region from the compressed air ejecting means. The compressed air negates the suction pressure and removes the rod-like article from the transport groove.
In order to improve the production capacity of the filter cigarette manufacturing machine, the speed at which rod-like articles are transported along the transport path, accordingly, the speed at which the removing drum rotates tends to be more increased. In this case, since each transport groove passes through the suction holding region in a shorter time, the compressed air ejecting means for selectively supplying compressed air to the suction holding region, more specifically, a removing valve thereof needs to be switched over more quickly.
However, even if the removing valve itself can be switched over at a high speed, it is impossible to generate a desired compressed-air pressure, or a desired removing pressure in the suction holding region immediately after the removing valve is switched over, because of the compressibility of air. Response delay in generating the removing pressure is unavoidable.
In order to deal with this response delay, it is thinkable to broaden the suction holding region in the removing-drum circumferential direction to make the time in which the removing pressure is supplied longer. In this case, however, when a transport groove holding a rod-like article to be sampled or removed is still in the suction holding region, the subsequent transport groove comes in the suction holding region. Thus, the removing pressure supplied to the suction holding region removes also a rod-like article in the subsequent transport groove at the same time.
Further, when a transport groove not holding a rod-like article comes in the suction holding region, the pressure in the suction holding region increases to the atmospheric pressure through the suction holes of this empty transport groove. In this case, the transport grooves immediately before and after the empty transport groove cannot receive enough suction pressure from the suction holding region, so that rod-like articles fall off these transport grooves.
An object of the invention is to provide a removing apparatus which allows high-speed rotation of the removing drum, ensuring that rod-like articles are removed only from intended transport grooves.
In order to attain the above object, a removing apparatus for rod-like articles according to the invention comprises a rotatable removing drum forming part of a transport path for rod-like articles, a suction means, a suction holding region, and a compressed air ejecting means.
The removing drum has a plurality of transport grooves for each receiving a rod-like article. The transport grooves are arranged at an outer circumferential surface of the removing drum with equal spaces between them in the circumferential direction thereof, and each have a suction hole, where each of the transport grooves has its suction hole at a different axial position of the transport groove than a transport groove adjacent to the transport groove in the circumferential direction of the removing drum has, so that the transport grooves are classified into a plurality of transport-groove types according to the position of the suction hole.
The suction means includes a suction supply region extending in the circumferential direction of the removing drum. The suction means is so provided as to supply suction pressure to the transport grooves through their suction holes while the transport grooves are passing through the suction supply region when the removing drum is rotating, to hold rod-like articles in the transport grooves by suction.
The suction holding region severs the suction supply region. The suction holding region has a plurality of independent holding passages each associated with one of the transport-groove types. The holding passages are arranged in parallel and each extend longer in the removing-drum circumferential direction than the distance between the transport grooves. The holding passages are so provided that the holding passages are each connected to the suction holes of transport grooves of their associated transport-groove type while the transport grooves are passing through the suction holding region, to thereby supply predetermined holding pressure to the transport grooves of their associated transport-groove type through the suction holes to hold suction of the rod-like articles in the transport grooves.
The compressed air ejecting means is provided for selectively removing rod-like articles from the transport grooves by compressed air while the transport grooves are passing through the suction holding region. The compressed air ejecting means comprises a plurality of independent supply passages each associated with one of the transport-groove types. The supply passages are so provided as to supply compressed air to the transport grooves while the transport grooves are passing through the suction holding region, to thereby negate suction of rod-like articles in the transport grooves. The supply passages are opened and closed by solenoid-operated valves.
Specifically, the removing drum includes a stationary sleeve member having the suction holding region on its outer circumferential surface, and a drum shell rotatably mounted on the outer circumferential surface of the stationary sleeve member and having the transport grooves.
In the above-described removing apparatus, while a transport groove holding a rod-like article to be removed is passing through the suction holding region, the compressed air ejecting means supplies compressed air to that particular transport groove. The supplied compressed air negates the suction of the rod-shaped article which is effected by the holding pressure in the holding passage associated with the transport-groove type of that particle transport groove. Thus, the rod-like article is removed from the transport groove.
After the rod-like article is removed from the transport groove, the holding passage associated with the transport-groove type of that transport groove is open to the atmosphere through the suction hole of that transport groove. However, the holding pressure in the holding passages associated with the other transport-groove types are maintained although the rod-like article was removed. Since the suction holding region is longer than the pitch between the transport groves, the subsequent transport groove comes in the suction holding region while the transport groove from which the rod-like article was removed is still in the suction holding region. Even so, the subsequent transport groove can move into the suction holding region, stably holding a rod-like article by suction.
When an empty transport groove comes in the suction holding region, the passage associated with the transport-groove type of that empty transport groove is open to the atmosphere through the suction hole of that empty transport groove. However, also in this case, the holding pressure in the passages associated with the other transport-groove types are maintained. Hence, the subsequent transport groove can move into the suction holding region, stably holding a rod-like article by suction.
As mentioned above, the suction holding region extends longer in the removing-drum circumferential direction than the pitch between the transport grooves. This means that the time in which compressed air, or in other words, removing pressure is supplied from the compressed air ejecting means to a transport groove is correspondingly long. Hence, even if there is response delay in raising the removing pressure, high-speed rotation of the removing drum is allowed, ensuring that rod-articles are removed reliably.
The supply passages are each connected with the holding passage associated with the same transport-groove type. In this case, a rod-like article in a transport groove is removed by compressed air which is ejected from the associated holding passage through the suction hole.
The compressed air ejecting means may includes ejecting holes formed in the transport grooves, and a plurality of independent ejecting grooves each associated with one of the transport-groove types. The ejecting holes are located at different axial positions of the transport groove, depending on the transport-groove types. The spurting grooves extend in parallel with the holding passages in the suction holding region and are each connected with the supply passage associated with the same transport-groove type. The ejecting grooves are so provided that the ejecting grooves are each connected to the ejecting holes of transport grooves of their associated transport-groove type while the transport grooves are passing through the suction holding region.
When the above-described compressed air ejecting means is provided, a rod-like article in a transport groove is removed by compressed air which is ejected from the associated ejecting groove through the ejecting hole into the transport groove.
The compressed air ejecting means may further include connection holes each connecting a holding passage and an ejecting groove associated with the same transport-groove type. In this case, a rod-like article in a transport groove is removed by compressed air which is ejected through not only the ejecting hole but also the suction hole.
The suction means may include a plurality of suction slots formed in the outer circumferential surface of the stationary sleeve member. The suction slots extend in the suction supply region and are connectable with the suction holes of the transport grooves. The suction holding region further includes connection passages connecting each of the holding passages with an associated one of the suction slots. In this case, the holding pressure in each holding passage comes from the suction pressure in the associated suction slot.
Each connection passage may have a throat for determining the holding pressure in its associated holding passage. The throat produces holding pressure in the holding passage, which is weaker than the suction pressure in the associated suction slot. This makes it possible to remove a rod-like article with a low-pressure compressed air. Thus, the compression air ejecting means may supply low-pressure compressed air to a transport groove.
The removing drum may form part of a transport path in a filter cigarette manufacturing machine, and be provided for removing cigarettes, double filter cigarettes or filter cigarettes transported along the transport path as rod-like articles.